1. Field of the Invention
The present invention relates to an inkjet head used in an inkjet recording apparatus for ejecting ink onto a recording medium to perform printing.
2. Description of the Related Art
An inkjet head is formed so that ink supplied from an ink tank to manifolds is distributed into a plurality of pressure chambers and that pulse-like pressure is selectively applied to the plurality of pressure chambers to thereby eject ink from a nozzle connected to each selected pressure chamber. As a device for applying pressure to the plurality of pressure chambers selectively as described above, there has been proposed an inkjet head having ceramic piezoelectric sheets disposed so as to be laid over the plurality of pressure chambers (e.g. see JP-A-2003-165215 (Page 5; and FIG. 5)).
In the inkjet head, a plurality of piezoelectric sheets are disposed stratiformly over the plurality of pressure chambers arranged on a plane. A plurality of surface electrodes that is formed so as to be long and narrow in one direction and correspond to the plurality of pressure chambers respectively are provided in the form of a matrix on the uppermost piezoelectric sheet of the laminated piezoelectric sheets. On the other hand, inner electrodes connected to the surface electrodes through through-holes and a common electrode provided so as to be common to the plurality of pressure chambers and kept at ground potential are provided between the plurality of piezoelectric sheets. A contact portion is provided at one end portion of each surface electrode. All the contact portions of the surface electrodes are arranged so as to face in one and same direction. Flexible printed circuit sheets (hereinafter referred to as FPC sheets) including signal lines for supplying the drive signals to the contact portions are disposed on an upper surface of the uppermost piezoelectric sheet. The FPC sheets are connected to the contact portions by means of soldering.
When a drive signal is supplied to the contact portion of a surface electrode through corresponding one of the signal lines of the FPC sheets, a voltage is applied between the surface electrode/inner electrode and the common electrode. Thus, the piezoelectric sheet is distorted to change the volume of a corresponding pressure chamber, to thereby eject ink from a nozzle connected to the pressure chamber.